A generic engine assembly comprising an internal combustion engine and an expander, which can be coupled thereto in a force-transferring manner, is known from DE 10 2012 204 368 B4. The internal combustion engine thereby serves to drive a first shaft, wherein a fluid-operated coupling arrangement, which can be operated at overpressure or underpressure, can couple a steam engine to a second shaft for driving purposes. A freewheel, which cooperates with the coupling arrangement, is thereby arranged between the first shaft and the second shaft, to transfer a rotational movement of the second shaft to the first shaft in a first operating mode and to be able to realize a free run of the first shaft relative to the second shaft in a second operating mode. To start the expander, a hydraulically or pneumatically operable coupling is used, respectively, which transfers an initial torque, which is required for the starting, to the expander in the closed state.
A further engine assembly is known from DE 10 2012 204 369 A1.
To be able to increase the efficiency of modern motor vehicles, so-called expanders, for example axial piston engines, are increasingly being used in the context of heat recovery systems, wherein such expanders are able to convert heat, which has gone unused to date by an internal combustion engine, for example, into mechanical energy. If such an expander is embodied as axial piston engine, for example, the latter typically requires a first start impulse to be able to be set into rotation. Different methods can be used for this purpose. For example, this can be realized within the expander by means of a mere supply of steam, whereby it is also conceivable in the alternative that a coupling to the internal combustion engine is used and, in response to directly feeding the generated mechanical energy of the expander into the drive train, is brought into an operative connection therewith.
However, it is a disadvantage of the starting devices known from the prior art that they are constructed in a comparatively complex manner and are thus not only technically vulnerable but are also expensive to produce.